1. Field
Embodiments of the present invention relate to a display device capable of sensing touch.
2. Description of the Related Art
Touch screen panels are used as input units of smart phones and smart pads, which are currently widely used. A touch screen panel is an input device capable of enabling the selection of information or content displayed on a screen of a display device by using a user's finger to input the user's command. Therefore, the touch screen panel is provided on a front face of the display device to convert a contact position of the user's finger into an electrical signal. Therefore, the instruction contact selected by the contact position is received as an input signal.
Since the touch screen panel may replace other input devices coupled to the image display device, such as a keyboard and a mouse, the use range thereof is increasing.
Methods of realizing a touch screen panel include a resistance layer method, a photo-sensing method, and an electro-capacitive method. Among the above methods, the electro-capacitive touch screen panel is widely used, and detects change in capacitance between conductive sensing patterns and other peripheral sensing patterns or a ground electrode when the finger contacts the touch screen panel, thereby converting the contact position into the electrical signal.
The electro-capacitive touch screen panel is commonly attached to the external surface of a display device, such as a liquid crystal display (LCD) and an organic light emitting display (OLED). However, since an additional touch screen panel is attached to the display device, the overall thickness and manufacturing cost of the display device increase, and visibility of an image deteriorates due to a gap between the touch screen panel and a display panel.
In addition, since a display device driving integrated circuit (IC) and a touch screen panel driving IC are additionally provided, products are not easily compatible with each other. Since the display device driving IC and the touch screen panel driving IC are coupled to separate flexible printed circuit boards (FPCB), respectively, manufacturing processes are complicated and product cost increases.
In addition, recently, a pen enabling a pen input function capable of performing more delicate or more precise work, as compared to that of a finger touch, are increasingly desired. A pen applied to the conventional electro-capacitive touch screen panel generates a specific signal by internal battery power supply, and the sensing electrodes of the touch screen panel sense the signal. However, since a battery is mounted in the pen, the size of the pen increases, and the battery must be changed periodically.